A lower power DC-DC converter (LDC) in a hybrid vehicle supplies load to a vehicle electronic component and is also capable of charging an auxiliary battery. The LDC variably adjusts a voltage to effectively manage power in a vehicle and operates to charge or discharge a battery based on a driving mode of the vehicle. Further, the LDC adjusts a voltage to periodically refresh an auxiliary battery to enhance durability of a battery. In particular, a charging degree of the battery is enhanced during a refresh operation, which adversely affects fuel efficiency of a vehicle.